Kerttula Anne-Marie, Lyytikäinen Outi, Kardén-Lilja Minna, Ibrahem Salha, Salmenlinna Saara, Virolainen Anni, Vuopio-Varkila Jaana
Department of Microbiology, National Public Health Institute, Helsinki, Finland.
BMC Infect Dis. 2007 Aug 14;7:94. doi: 10.1186/1471-2334-7-94.
In Finland, the annual number of MRSA notifications to the National Infectious Disease Register (NIDR) has constantly increased since 1995, and molecular typing has revealed numerous outbreak isolates of MRSA. We analyzed the data on MRSA notifications of the NIDR, and MRSA isolates were identified mainly by pulsed-field gel electrophoresis (PFGE) at the National Reference Laboratory (NRL) in Finland during 1997-2004. One isolate representative of each major PFGE type was further characterized by multilocus sequence (MLST)-, staphylococcal cassette chromosome mec (SCCmec)-, and Panton-Valentine leukocidin (PVL)-typing.
The annual number of MRSA notifications to the NIDR rose over ten-fold, from 120 in 1997 to 1458 in 2004, and the proportion of MRSA among S. aureus blood isolates tripled, from <1% during 1997-2003 to 2.8% in 2004. During the same period of time, 253 different strains among 4091 MRSA isolates were identified by PFGE: 215 were sporadic and 38 outbreak/epidemic strains, including 24 new strains. Two epidemic strains resembling internationally recognized MRSA clones accounted for most of the increase: FIN-16 (ST125:IA) from <1% in 1997 to 25% in 2004, and FIN-21 (ST228:I) from 6% in 2002 to 28% in 2004. Half of the ten most common strains carried SCCmec IV or V.
The predominant MRSA strains seem to change over time, which encourages us to continue implementing active control measures with each new MRSA case.
在芬兰，自1995年以来，每年向国家传染病登记处（NIDR）报告的耐甲氧西林金黄色葡萄球菌（MRSA）病例数持续增加，分子分型显示有大量MRSA暴发菌株。我们分析了NIDR的MRSA报告数据，1997 - 2004年期间，芬兰国家参考实验室（NRL）主要通过脉冲场凝胶电泳（PFGE）鉴定MRSA分离株。每种主要PFGE类型的一个代表性分离株进一步通过多位点序列（MLST）、葡萄球菌盒式染色体mec（SCCmec）和杀白细胞素（PVL）分型进行特征分析。
向NIDR报告的MRSA病例数增长了十倍多，从1997年的120例增至2004年的1458例，MRSA在金黄色葡萄球菌血培养分离株中的比例增至原来的三倍，从1997 - 2003年期间的<1%增至2004年的2.8%。在同一时期，通过PFGE在4091株MRSA分离株中鉴定出253种不同菌株：215株为散发病例，38株为暴发/流行菌株，包括24株新菌株。两种类似于国际公认的MRSA克隆的流行菌株占病例增加的大部分：FIN - 16（ST125:IA）从1997年的<1%增至2004年的25%，FIN - 21（ST228:I）从2002年的6%增至2004年的28%。十种最常见菌株中有一半携带SCCmec IV或V。
主要的MRSA菌株似乎随时间变化，这促使我们继续对每一例新的MRSA病例实施积极的控制措施。
